Nate Silver confirms that right of center politicians are almost totally absent these days as graduation speakers in the Ivory Tower. Lots of lip service is given to tolerance and a preference for diversity. That's the PC thing to do, particularly among those who like to think they are enlightened. The reality is very different. Click on the poll on that which Nate links in his article.
Part of the problem is that the Democrats haven't really done anything that would get students riled up and part is that while all politicians prefer speaking to like-minded people, conservatives have been more prone to that because they could afford to. They still act like they can do that because they don't seem to have truly grasped that the political ground has eroded out from underneath them nationally because regionally they still have solid ground.